// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MEDIA_BASE_DECRYPT_CONFIG_H_
#define MEDIA_BASE_DECRYPT_CONFIG_H_

#include <stdint.h>

#include <iosfwd>
#include <string>
#include <vector>

#include "base/macros.h"
#include "media/base/media_export.h"
#include "media/base/subsample_entry.h"

namespace media {

// Contains all information that a decryptor needs to decrypt a media sample.
class MEDIA_EXPORT DecryptConfig {
public:
    // Keys are always 128 bits.
    static const int kDecryptionKeySize = 16;

    // |key_id| is the ID that references the decryption key for this sample.
    // |iv| is the initialization vector defined by the encrypted format.
    //   Currently |iv| must be 16 bytes as defined by WebM and ISO. Or must be
    //   empty which signals an unencrypted frame.
    // |subsamples| defines the clear and encrypted portions of the sample as
    //   described above. A decrypted buffer will be equal in size to the sum
    //   of the subsample sizes.
    DecryptConfig(const std::string& key_id,
        const std::string& iv,
        const std::vector<SubsampleEntry>& subsamples);
    ~DecryptConfig();

    const std::string& key_id() const { return key_id_; }
    const std::string& iv() const { return iv_; }
    const std::vector<SubsampleEntry>& subsamples() const { return subsamples_; }

    // Returns true if the corresponding decoder buffer requires decryption and
    // false if that buffer is clear despite the presense of DecryptConfig.
    bool is_encrypted() const { return !key_id_.empty() && !iv_.empty(); }

    // Returns true if all fields in |config| match this config.
    bool Matches(const DecryptConfig& config) const;

    // Prints to std::ostream.
    std::ostream& Print(std::ostream& os) const;

private:
    const std::string key_id_;

    // Initialization vector.
    const std::string iv_;

    // Subsample information. May be empty for some formats, meaning entire frame
    // (less data ignored by data_offset_) is encrypted.
    const std::vector<SubsampleEntry> subsamples_;

    DISALLOW_COPY_AND_ASSIGN(DecryptConfig);
};

} // namespace media

inline std::ostream& operator<<(std::ostream& os,
    const media::DecryptConfig& obj)
{
    return obj.Print(os);
}

#endif // MEDIA_BASE_DECRYPT_CONFIG_H_
